Improvement in let-off mechanism foe looms



@uiten V'tgatrs gstrnt .ffice WILLIAM HALL, OF N ORTH ADAMS, MASSACHUSETTS, ASSIGNOR TO HIM- SELF AND JOHN W. PITT, OF SAME PLACE.

Letters Patent No. 80,625, dated August 4, 1868.

IMPROVEMENT LET-OFF MBGHANISM POR LOOMS.

TO ALL WHOM IT MAY CONOERN:

Be it known that I, WILLIAM HALL,.of North Adams, in the Vcounty of Berkshire, and State of Massachusetts, have invented a new en d improved Let-Off Mechanism for Looms and other machines and I- do hereby declare that the following is a full, cleai, and exact description thereof, which will enable those skilled in the art to make and use the same, reference being had to the accompanying drawings, forming part of this specification. Y l

This invention relates to a new and improved I etoit` mechanism for looms and other machines in which a warp or web is required to be unwound or let oi from a shaft with as uniform a tension as possible.

The object ofthe invention is to' obtain a simple means to eiect the above result, and one which will vkeep the warp or web at a uniform tension throughout, or from the commencement of the let-ofi` to the end ofthe same.

`In the accompanying sheet of drawings- Figure 1 is a side view of my invention.

Figure 2, a front view of the same.

Similar letters of reference indicate corresponding parts.

A represents a shaft, on which the warp or web is wound.

One journal, a, of this shaft is fitted in a. fixed bearing, b, on the loom or other machine, and the other` journal, at', is tted on a bearing, c, which Ais pivotcd to the machine, as shown at d, said bearing extending for:l

ward, and having aber, e, extending down from it, as shownclearly in iig. 1.

This bearing c and b ar e form what maybe termeda bent lever, having d for its fulcrum.

The lower lend of the 'bar eof this lever has two Vhookmff, tted to iton which the ends ofthe belt B are secured, and this belt passes over a pulley, g, on shaft A, a greateror less degree of tensionbeing given the belt v by turning screw-nuts, t, on the lower ends of the hoolrs.

To the front end of the bearingl c there is connected one 4end of a spiral spring, c', the opposite -end being attached to the frame of the'machine.

This sprin'g'has a tendency to keep the har c elevated to a certain citent, and the belt B rather loose on the pulley, g.

By depressing-the bar e, thctcnsiou of the belt B is increased, as will be fully understood by referring to .y

iig. 1.

From the above description it will be seen that .when the warp or web on thc shaft A is first put into the machine, its weight will keepthe' bar e considerably depressed, `and the belt-B comparatively taut, so that the friction thus produced will compensate for the length oflcverage due to the large diameter of the warp or web. As, however, thc warp or web is unwoun'dfrom the shaft, the diameter of the former, and consequently the leverage-power, correspondently decreases; and also lthe weight of the web, and the arm e graduallyrrising under the action of the spring z', the tension of the belt B gradually relaxes and decreases the friction, thereby compensating for the reduction o f leverage, and rendering the tension of the warp or web uniform throughout.

I claim as new, and desire to secure by Letters Patent- The pivoted bearing c with the bar e attached, in combination with belt B, pulley g, otn shaft A, and spring t', all constructed and'arranged substantially as and for the purpose set forth.

' WILLIAM HALL.

Witnesses:

A. G. POTTER, EDWIN Tuner.. 

